Screens have now become a common part of many young children’s lives, raising more and more questions about how early exposure may affect development over time.
A new longitudinal study, which followed children from age 1 to age 8, found that greater screen use, especially during infancy and around the time children start school, was associated with lower academic performance at age 9 and poorer working memory at age 10.5. The results suggest that the timing of children’s exposure to screens may be as important as the amount of time they spend using them.
The World Health Organization (WHO) and the American Academy of Pediatrics recommend avoiding screen use before the age of 18–24 months and limiting it to less than one hour per day for children aged 2 to 5 years.
However, many children spend more time in front of screens than these guidelines recommend. Research on the effects of screen use on cognitive development has also yielded mixed results. Most previous studies have been based on assessments conducted at a single point in time, have focused primarily on school-aged children, or have not included repeated measurements throughout early childhood.
Studies that follow children through several stages of development can help identify periods when screen exposure may be particularly important, while also better taking into account family and environmental factors.
Tracking screen time from infancy to childhood
Researchers from Inserm and the National University of Singapore conducted the study, which was published in the World Journal of Pediatrics. Using data from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) birth cohort, the team looked at parent-reported screen use at six different ages. The researchers then compared these measurements with the children’s academic performance and working memory several years later.
The analysis included 502 children, who were followed from infancy to middle childhood. Greater screen use during certain developmental stages was associated with poorer later academic performance and poorer working memory. The clearest patterns emerged for screen exposure during infancy and near the start of formal schooling, suggesting that these periods may be particularly sensitive for cognitive development.
Children who had more screen exposure overall during childhood also tended to perform worse academically. Taken together, the findings suggest that total screen time is only part of the bigger picture. The age at which screen use peaks may also be important, with early childhood representing a period when screen habits have long-term consequences for learning and memory.
Age 1 showed the strongest connection
“The effect sizes we saw at age 1 were the largest of all the time points we examined,” the authors said. “This suggests that early infancy may be a period of heightened sensitivity, when the developing brain is particularly vulnerable to the replacement of learning-promoting interactions with screen time. We were also surprised to see that, while screen use at ages 2 and 3 showed no significant associations, these associations reemerged at age 6, when children begin formal schooling. So it’s not just about the early years; screen use later in childhood still matters.”
The pattern was not the same at every age. Screen use at ages 2 and 3 was not significantly associated with the later outcomes measured in the study, but this association emerged again at age 6. This coincides with the transition to formal education, when children face increasing demands on attention, memory, and learning.
Why screen time may matter
According to the researchers, the results support the general principle that “less is more” when it comes to children’s exposure to screens. An extra hour of screen time each day may not have a noticeable effect on each child individually, but relatively small changes across the population could lead to a significant number of children having poorer academic outcomes.
Therefore, efforts to reduce screen time may be most beneficial when they begin in infancy and are reinforced as children approach school age. The researchers also caution that screen time alone does not tell the whole story. Future studies should examine whether developmental outcomes vary depending on the quality of content children watch, the type of device used, and whether parents watch with their children./ScienceDaily